This invention relates to an image forming apparatus that conveys a recording unit in a main scanning direction and makes the recording unit eject ink drops during the conveyance of the recording unit, thereby to form an image onto a sheet passing in a sub-scanning direction.
An image forming apparatus according to an ink-jet recording method is conventionally known. In the image forming apparatus according to the ink-jet recording method, generally, a recording unit ejects ink drops while moving at a constant speed in a main scanning direction. Thereby, an image is formed onto a sheet passing in a sub-scanning direction.
Specifically, in the conventional image forming apparatus, ink drops are ejected while the recording unit is moved at a constant speed. As a result, misalignment of landing positions of the ink drops is avoided and a uniform image without unevenness is formed.
Also, in the image forming apparatus of this type, the recording unit reciprocates and ejects ink drops in each of the outward and homeward journeys, thereby to form an image onto a sheet at a high speed.
In case that an image forming operation is performed as described above in each of the outward and homeward journeys, it is necessary to accurately stop the recording unit at return points. Otherwise, a distance from a stop position to an image forming start position may fluctuate upon performing the image forming operation for the next line after the stop of the recording unit.
In a known technique for stopping the recording unit accurately at a target stop position which may solve the above problem, the recording unit is conveyed at a low speed before the target stop position, and control of the recording unit is switched from speed control to position control in a vicinity of the target stop position. In this manner, the recording unit is stopped at the target stop position with high precision.